Transplantation is a life-saving therapy but is seriously limited by the scarcity of donor organs. In contrast to native tissue and organ transplantation from a nonautologous donor, tissues and organs generated through tissue engineering provide a more abundant alternative source for highly sought after biological materials. Scaffolding plays a pivotal role in the engineering of new tissues and organs by providing a support and a framework within which blood vessels, lymphatic vessels, and nerves may course.
Collagen is a natural extracellular matrix component of many tissues such as bone, skin, tendon, ligament, and other connective tissues. Collagen's fibrillar structure is important for cell attachment, proliferation, and differentiation.
Collagen fiber bundles vary in diameter from 50 to 500 nm. As a natural extracellular matrix component, collagen facilitates cellular recognition. Cellular recognition is advantageous for promoting cell attachment and infiltration. Importantly, however, cellular recognition may also precipitate a deleterious inflammatory or pathological immunogenic response. Native collagen is also undesirable as an implant or prosthesis due to the inherent batch to batch variability in mechanical specifications and degradability of said native collagen derived from biological sources.
In contrast, aliphatic polyesters such as (but not limited to) poly(lactide), poly(glycolide) and their copolymers are biodegradable, biocompatible (e.g., non-immunogenic), and among the few synthetic polymers approved by FDA for some human clinical applications. The prior art presents three-dimensional porous structures fabricated from synthetic aliphatic polyesters employed for cell attachment, growth, and tissue regeneration. However, these porous scaffolds (in the prior art) do not approximate the fibrillar morphology of a native collagen extracellular matrix.
In an attempt to approximate a native collagen extracellular matrix, the prior art has applied textile technology to produce nonwoven fabrics from aliphatic polyesters. These nonwoven fabrics, however, require the expensive and laborious steps of fiber extrusion, drawing, crimping, cutting into stable fibers, carding, needling, heat platen pressing, degreasing, and punching. Furthermore, said textile produced nonwoven fabrics are associated with structural parameters (as compared with native collagenous matrices) that do not favor cell attachment (e.g., large fiber diameter and low surface to volume ratios).
What is needed, therefore, is a biocompatible synthetic fibrillar matrix (readily fashioned into a desired shape) that reproduces the form and function of native collagenous extracellular matrices.